Technical Field of the Invention
This invention relates to a steering and reversing system for a marine jet propulsion unit for a water craft.
Basically, a jet propulsion unit for a water craft comprises a pump, usually an axial-flow pump, supported in the craft, typically in the stern thereof, the inlet of which is connected with a water intake in the bottom of the craft and the outlet of which is connected with a rearwardly directed discharge tube or nozzle, usually projecting rearwardly beyond the transom of the craft, for discharging the craft-propelling water jet.
For side steering of the craft, a mechanism is provided to deflect the water jet, or at least a part of it, laterally in either direction, and for slowing down the craft and/or making it go astern, a reversing mechanism is provided to deflect the water jet at least partially in the forward direction, usually downwardly and forwardly.
In the known water jet propulsion units, the side steering is usually accomplished by pivoting the nozzle, or the rear part of it, about a vertical axis by means of one or more actuators, commonly in the form of hydraulic cylinders. The reversal of the thrust of the water jet usually is accomplished by a separate reversing mechanism which is mounted in or behind the nozzle and comprises one or more flaps or scoop-like elements which are operable by means of one or more actuators, commonly hydraulic cylinders, to intercept the water jet and divert at least a portion of it in the desired direction, usually downwardly and forwardly.
Known side-steering and reversing systems thus comprise a large number of movable elements and actuators and therefore are complicated, space-consuming, heavy and expensive.